package com.thinkgem.jeesite.common.utils;


import java.io.IOException;

import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Lazy;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.stereotype.Service;

/**
 * 以静态变量保存Spring ApplicationContext，可在任何代码任何地方任何时候取出ApplicationContext
 * @author Zaric
 *
 */
@Service
@Lazy(false)
public class SpringContextHolder implements ApplicationContextAware, DisposableBean {

	private static ApplicationContext applicationContext = null;
	
	private static Logger logger = LoggerFactory.getLogger(SpringContextHolder.class);
	
	/**
	 * 检查ApplicationContext不为空
	 */
	private static void assertContextInjected(){
		Validate.validState(applicationContext != null , "applicationContxt属性未注入，请在applicationContext.xml中定义SpringContextHolder.");
	}
	/**
	 * 取得存储在静态变量中的ApplicationContext
	 */
	public static ApplicationContext getApplicationContext(){
		assertContextInjected();
		return applicationContext;
	}
	
	public static String getRootRealPath(){
		String rootRealPath = "";
		try {
			rootRealPath = getApplicationContext().getResource("").getFile().getAbsolutePath();
		} catch (IOException e) {
			logger.warn("获取系统根目录失败");
		}
		return rootRealPath;
	}
	
	public static String getResourceRootPath(){
		String rootRealPath = "";
		try {
			rootRealPath = new DefaultResourceLoader().getResource("").getFile().getAbsolutePath();
		} catch (IOException e) {
			logger.warn("获取资源根目录失败");
		}
		return rootRealPath;
	}
	/**
	 * 从静态变量applicationContext中获取Bean，自动转为所赋值对象的类型
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String name){
		assertContextInjected();
		return (T) applicationContext.getBean(name); 
	}
	/**
	 * 从静态变量applicationContext中获取Bean，自动转型为所赋值对象的类型
	 */
	public static <T> T getBean(Class<T> requiredType){
		assertContextInjected();
		return applicationContext.getBean(requiredType); 
	}
	/**
	 * 清除SpringContextHolder中的ApplicationContext为null
	 */
	public static void clearHolder(){
		if(logger.isDebugEnabled()){
			logger.debug("清除SpringContextHolder中的ApplicationContext对象："+ applicationContext);
		}
		applicationContext = null;
	}
	/**
	 * 实现DisposableBean接口，在Context关闭时清理静态变量
	 */
	@Override
	public void destroy() throws Exception {
		SpringContextHolder.clearHolder();
	}
	/**
	 * 实现ApplicationContextAware接口，注入Context到静态变量中
	 */
	@Override
	public void setApplicationContext(ApplicationContext applicationContext)
			throws BeansException {
		logger.debug("织入ApplicationContext到SpringContextHolder : {}",applicationContext);
		if(SpringContextHolder.applicationContext != null){
			logger.info("SpringContextHolder中的ApplicationContext被覆盖，原有的ApplicationContext为： " + SpringContextHolder.applicationContext);
		}
		SpringContextHolder.applicationContext = applicationContext;
	}
	
}
